Introduction to General, Organic, and Biochemistry 12th Edition

Book Preface

We wish to sincerely thank our colleagues who not  only adopted the previous editions for their courses but also offered  sage advice on suggested changes and updates to this edition.
With all the continuous advances in the field, this edition emphasizes the  inclusion of new relevant concepts and examples in this fast growing discipline, especially in the biochemistry chapters. Based on valuable feedback  from reviewers, we also strive to consolidate content in a more meaningful  and manageable manner while preserving an integrated view of chemistry.

This new edition continues with the tradition of providing a solid foundation  on which instructors can build upon, and chapter resources are conceived  and written with flexibility in mind, affording instructors the opportunity  to seamlessly select applicable topics for discussion with their students. The  wealth of problems, both practical and challenging, provide students with  numerous ways to test their knowledge from a variety of viewpoints.
From the very beginning of the book, we include organic compounds and  biochemical substances to illustrate relevant and overlapping principles.  This progression ascends from the simple to the complex. We encourage our  colleagues to advance to the chapters of biochemistry as quickly as possible,  because there lies most of the material that is relevant to the future professions of our students.

Audience and Unified Approach
This book is intended for non-chemistry majors, mainly those entering  health sciences and related fields, such as nursing, medical technology,  physical therapy, and nutrition. In its entirety, it can be used for a one-year  (two-semester or three-quarter) course in chemistry, or  parts of the book can be used in a one-term chemistry  course.
We assume that the students using this book have  little or no background in chemistry. Therefore, we introduce the basic concepts slowly at the beginning and  increase the tempo and the level of sophistication as we  go on. We progress from the basic tenets of general chemistry to organic and then to biochemistry. Throughout, we  integrate the parts by keeping a unified view of chemistry. For example, we frequently use organic and biological  substances to illustrate general principles.

While teaching the chemistry of the human body is  our ultimate goal, we try to show that each subsection  of chemistry is important in its own right, besides being  necessary for understanding future topics.

Chemical Connections (Medical and Other  Applications of Chemical Principles)
The Chemical Connections boxes contain applications of the principles discussed in the text. Comments from users of earlier editions indicate that  these boxes have been especially well received, and provide a much-requested  relevance to the text. For example, in Chapter 1, students can see how cold  compresses relate to waterbeds and to lake temperatures (Chemical Connections 1C). New up-to-date  topics include coverage of omega-3 fatty acids and  heart disease (Chemical Connections 21F), and the  search for treatments for cystic fibrosis (Chemical  Connections 26F).

The inclusion of Chemical Connections allows for  a considerable degree of flexibility. If an instructor  wants to assign only the main text, the Chemical  Connections do not interrupt continuity, and the essential material will be covered. However, because  they enhance the core material, most instructors  will probably wish to assign at least some of the  Chemical Connections. In our experience, students  are eager to read the relevant Chemical Connections, without assignments, and they do with discrimination. From such a large number of boxes, an  instructor can select those that best fit the particular needs of the course. So that students can test  their knowledge, we provide problems at the end of each chapter for all of the  Chemical Connections; these problems are now identified within the boxes.

Metabolism: Color Code

The biological functions of chemical compounds are explained in each of  the biochemistry chapters and in many of the organic chapters. Emphasis  is placed on chemistry rather than physiology. Positive feedback about the  organization of the metabolism chapters has encouraged us to maintain the  order (Chapters 26–27).

First, we introduce the common metabolic pathway through which all food  is utilized (the citric acid cycle and oxidative phosphorylation), and only after  that do we discuss the specific pathways leading to the common pathway. We  find this a useful pedagogic device, and it enables us to sum the caloric values  of each type of food because its utilization through the common pathway has  already been learned. Finally, we separate the catabolic pathways from the  anabolic pathways by treating them in different chapters, emphasizing the  different ways the body breaks down and builds up different molecules.

The topic of metabolism is a difficult one for most students, and we have  tried to explain it as clearly as possible. We enhance the clarity of presentation by the use of a color code for the most important biological compounds.

Each type of compound is screened in a specific color, which remains the  same throughout the three chapters. These colors are as follows:
ATP and other nucleoside triphosphates
ADP and other nucleoside diphosphates
The oxidized coenzymes NAD+ and FAD
The reduced coenzymes NADH and FADH2

Acetyl coenzyme A
2. Respiration Humans and animals get their energy by respiration. The  oxygen in the air we breathe oxidizes carbon-containing compounds in  our cells to produce CO2 and H2O. Note that respiration is equivalent  to combustion, except that it takes place more slowly and at a much  lower temperature. We discuss respiration more fully in Chapter 26.  The important product of respiration is not CO2 (which the body eliminates) or H2O, but energy.
3. Rusting We all know that when iron or steel objects are left out in the  open air, they eventually rust (steel is mostly iron but contains certain  other elements as well).

In figures showing metabolic pathways, we display the numbers of the  various steps in yellow. In addition to this main use of a color code, other  figures in various parts of the book are color coded so that the same color is  used for the same entity throughout. For example, in all figures that show  enzyme–substrate interactions, enzymes are always shown in blue and substrates in orange.